Foundations will be laid in this proposal for use of both functional magnetic resonance imaging (fMRI) maps and resting-state functional connectivity maps to study brain plasticity that occurs following surgery to repair peripheral nerves injured by trauma. A rat-brain model of nerve injury of the forearm will be developed at 9.4T. There are three well-focused aims. In Aim 1, two classes of novel radio frequency surface coils specifically tailored to the rat brain will be developed as follows: a one-turn with improved depth sensitivity and a 2X1 multichannel coil for whole rat-brain imaging. Aim 1 is dedicated to achieving increased fMRI spatial resolution using cubic voxels through use of multichannel arrays of small coils. Aim 1 serves the other two aims, each of which acquires rat fMRI and functional connectivity MRI (fcMRI) data. In Aim 2, electrical stimulation electrodes will be implanted on the individual peripheral nerves of the rat upper extremity, including the use of multiple electrodes. Extensive preliminary data for the major nerves are reported. Extension to high spatial resolution fMRI of the major nerves and also to smaller branching nerves using the multichannel coils of Aim 1 is proposed. High resolution resting-state functional connectivity maps also will be produced. This aim is directed to acquisition of normal high resolution fMRI maps of nerves of the forearm as well as corresponding high resolution resting-state functional connectivity maps. It provides a baseline for interpretation of the trauma and plasticity maps of Aim 3. In Aim 3, a rat model of nerve trauma is developed. A nerve is cut, and fMRI as well as functional connectivity maps are obtained at acute and sub-acute intervals after the injury. Functional MRI and functional connectivity maps will be acquired at high spatial resolution using the multichannel coils and signal processing methods of Aim 1, and the normative studies of Aim 2 will facilitate interpretation of observed brain plasticity. The overall significance of the project lies in the hypothesis that improved fMRI of the rat in a context of nerve injury will lead to improved models of human disease, and that the manipulations that are possible with a rat model will lead to improved human diagnosis and treatment. Specifically, a long-term goal is to address extremely debilitating injuries of the nerves of the forearm that occur in childbirth and also in adult trauma associated with motorcycle, snowmobile, and automobile accidents, and in military operations such as the Iraq and Afghanistan wars. In addition, the work proposed here is expected to contribute fundamentally to knowledge of brain plasticity following nerve injury. 2.